Hydrocarbon questions

[Turbogn]

I have been a member of this board for about 4 years but this will be my first post. I have always been able to use the search to find my answers but I want a more information and personal experience with this question.
Does anyone know why some of the suppliers of R-12a say to charge the systems at atmospheric pressure while others 10in hg and none in a hard vacuum? I found one suppliers who sells two versions of 12a. Enviro-safe Standard and Industrial. They say you can charge the Industrial in a vacuum but they don't mention how much vacuum? Does anyone here know why you should not pull a hard vacuum with hydrocarbons? Would it affect performance? If so why? Also, which way does the system work better?

[moondawn]

hi there i am sure i have read recently about this, something to do with the oil maybe being drawn away from the compressor.

hope someone can answer this as i am interested to know the answer too

cheers lee